Fitzgerald dunning and ebenezer emmet reid



Patented Aug. 28, 1928.

UNITED. STATES r 1,682,269 PATENT OFFICE.

FITZGERALD mnm'me AND nnnunzna EMMET REID, or summons; uAnYLANn, assrenons r HYNSON, was'rco'r'r & DUNNING, or BALTIMORE, MARYLAND, A

FIRM.

rnocnss FOR-THE rnonucrron or rnnmmr s rmmrc ACIDS.

No Drawing.

acid,

Stibanilic acid has been made heretofore by processesinvolving the d azotizationof acetyl-v -phenylene-d1amme (p-amlno-aeeta'nihde combining the dlazo compound wlth antimony trichloride, breaking down the resulting diazo-antimony compound and hydrol-yzing oif the acetyl group. Processes 1nvolving this general procedure are unsatisfacg0 tory because in the decomposition of the d1 a zo antimony compound a voluminous and stlfi foam is formed which is-very diflicult to handle and the yields of the stibanilic ac1dare low. p

We have devised a process for the production of stibanilic'acid according to whlch a relatively high yield, 65 percent or more of the theoretical, maybe obtained and int'which the difiiculties due to. foaming are largely '0 eliminated. The process is adapted to relatively large scale production. 4

In accordance with our invention the diazo antimonycompound is decomposed and the acetyl group simultaneously hydrolyzed off a by treatment with caustic soda at a relatively hlgh tem erature. The process is illustrated by the to lowing specific example: g

1 mole (150 g.) of p-amino-acetanilide: and mole (145 g.) of antimony trioxlde (sno are dissolved in suflicient concentrated (e. g. 30%) hydrochloric acid to prevent antimony oxychloride from precipitating. This solution, which may containcrystals of the hydrochloride of the p-aminoacetanilide, is diazotized with sodium nitrite, e. at 15% solution containing g. of Na in 460 cc. of water, by delivering the sodium nitritesolution through a capillary tube into bottom of the body of the hydro-- 60 chloric acid solution of the pamino-acetanilide and antimony oxide, while the latter is vigorouslv and continuously stirred. A

acid (p-amino-phenylstibinic Application filed January 6; 1927. semi mi. 159,499;

yellow crystalline molecular diazo antimony compound having probably the formula:

separates out and is filtered oil and suspended in water and the suspension is run slowly and in small portions into a 10% solution of 420 g. of caustic soda heated to 90 C. The solution foams vigorously upon each addition .of the suspension, but t e foam is not stiflf and quickly breaks down. When all of the suspension has been added and the reaction is com lete, the reaction mixture is almost neutralized and then treated with carbon dioxide to precipitate impurities. The solutionisthen' filtered and acidified with acetic'acid when a white amorphous product, p-amino-phenylstibinic or stibanilic acid is precipitated. The procedure illustratedin'the foregoing example, the main-. feature M. which is the decomposition of the diazo antimony compound by means of hot caustic soda, is capable ofconsiderable variation, for instance, with respect to the formation of the-diazo antimony compound and with respect to the-tempera tui'e and concentration of the caustic soda solu ion. The diazo antimony compound may be formed in any known or suitable way without departing from our'invention and the concentration o the caustic soda solution may be varied, so lon as the' essential feature, 1. e., the use of a ct solution (between and 100 C.) of caustic soda, as distinguished from previously employed cooled solutions, is adhered to, without departing from our invention as defined in the appended claims;

As has been indicated the procedure is applicable with advantage in the production of primar stibinic acids other than stibanilic acid, a though it is for the preparation of this compound that the process is particularly important at the present time. For the preparation of other stibinic acids, for in- RSbO H in which stands for an arematic residue, substituted or'not, which comprises dlazotlzlng a primary amme and combining the diazo compound with an antimony salt in an acid reaction medium, and decom posing the diazo antimony compound so formed by treating it with a hot caustic al kali solution.

2. Process for the production of stibanilic acid, which comprises dia'zotizing a solution of acetyl-phenylene-diamine and antimony oxide in by rochloric acid, and decomposing the resulting diazo antimony compound in a hot caustic alkali solution.

3. Process for the production of stibanilic acid, which comprises dissolving acetyl-pphenylene-diamine and antimony oxide in hydrochloric acid, diazotizing the solution with sodium nitrite, separating the resulting insoluble diazo-antimony compound, and introducing said diazo-antimony compound intoa hot aqueous solution of caustic alkali.

4. Process for the production of stibanilic acid as defined in claim 3 in which the dia-zoantimony compound in an aqueous suspension is introduced into a solution of caustic I acid, which comprises decomposing the diazoantimony compound of p-amino-acetanllide by means of a caustic alkali solution ata temperature of from 85 to 100 C.

In testimony whereof, we aflix our signatures.

FITZGERALD DUNNINGL EBENEZER EMMET REID. 

